1. Field of the Invention
The present invention relates to a device for the operating of a cruise control system of an automobile vehicle. It can be applied especially to vehicles equipped with means for checking the distance and/or the speed of obstacles located in the path of the vehicle, the pace of these vehicles being regulated or controlled as a function of the information on distance and/or speed given by said means. More generally, it can be applied to any vehicles fitted out with means for the automatic control of their pace.
2. Description of the Prior Art
There are known ways of equipping vehicles with means for the measurement of the distance and/or speed of vehicles or obstacles preceding them. These means, based on radar, optical or other techniques, can be used especially to carry out an automatic control of the speed of the vehicles as a function of the traffic. They are generally called adaptive or automative cruise control (ACC) devices.
These means provide information that may be exploited in different ways. One case of simple exploitation consists for example in providing a piece of visual information to the driver of the vehicle if a safety distance threshold is crossed. In this case, it is for the driver to take action, of his own accord, on the braking system of the vehicle.
A more elaborate case may implement a system of automatic braking by servo-linking the braking and/or acceleration system of the vehicle to the information given by the measurement means. In this case, the driver does not have any direct control over the pace of the vehicle. However it is necessary to provide for the possibility of giving him total command of the braking and/or acceleration system, independently of the information given by the distance and/or speed measurement means. To activate or deactivate the system for the automatic control of his vehicle, the driver generally activates a manual command device, for example a conventional push-button.
In the case of automative cruise control coupled to an ACC type radar, several manual commands are generally used. A first on/off manual command activates the automative cruise control system. A second manual command, also called a set/resume command, engages the automatic control system. In other words, with the system being in operation through the action taken on the on/off command, the engaging of the system starts up the automative cruise control system proper, namely for example the automatic control of acceleration and/or braking.
These manual commands are located, as the case may be, on a handle that is localized slightly behind the steering wheel or again on the steering wheel itself. Typically, to engage the automative cruise control system after having activated it by the on/off push-button, the driver of the vehicle presses the set/resume push-button. To activate the system, the driver may for example press the set/resume push-button a second time. A light indicator sometimes accompanied by a sound signal may for example remind the driver of the state—active or inactive—of the automative cruise control system.
This mode of control is especially well suited to the use of automative cruise control systems on motorways, for example in association with an ACC type radar. In this configuration, the periods of automative cruise control are lengthy and the traffic situation is unencumbered. The driver's work load for activating the push-buttons is light. The driver sees critical situations from afar. He therefore has sufficient time to react to these situations, especially to move his right foot in order to place it on the accelerator or brake.
In urban use, things are no longer the same. Several drawbacks appear. The periods of automatic driving are short and the driver constantly has to resume control in order to manage situations such as stopping at traffic lights, yielding to right of way, changing roads or taking sharp corners, for example. The above-described operation of the system by means of push-buttons then entails a work load and attention span that soon become unbearable for the driver. From the viewpoint of safety, this added preoccupation is not propitious, and is even dangerous. Furthermore, the driver must constantly look at his dashboard in order to know the state of his system.